* {
    margin: 0;
    padding: 0;
    list-style: none;
}

h1 {
    height: 50px;
    width: 100%;
    background: red;
    text-align: center;
    line-height: 50px;
}

h2 {
    height: 100px;
    background: green;
    width: 100%;
    text-align: center;
    line-height: 100px;
}

h2.active {
    position: fixed;
    top: 0;
}

.floor {
    width: 1200px;
    margin: auto;
}

.floor ul li {
    height: 500px;
    width: 1200px;
    line-height: 500px;
    text-align: center;
    font-size: 36px;
}

.floor ul li:nth-child(even) {
    background: pink;

}

.floor ul li:nth-child(odd) {
    background: skyblue;
}

.scroll {
    position: fixed;
    top: 50%;
    right: 20px;
    transform: translate(0, -50%)
}

.scroll ul {
    width: 80px;
}

.scroll ul li {
    width: 100%;
    height: 35px;
    line-height: 35px;
    text-align: center;
    border: 1px solid #ccc;
}

.scroll ul li.active {
    background: red
}